1. Field of Invention
The present invention relates to a method of reading data from the memory inside a scanner. More particularly, the present invention relates to a method of reading data from a synchronous dynamic random access memory (SDRAM) inside a scanner.
2. Description of Related Art
A scanner that uses dynamic random access memory (DRAM) can only access a batch of data in a memory at a time. Since the data access rate may directly affect the image-processing speed of a scanner, a fast-acting synchronous dynamic random access memory (SDRAM) is routinely employed to reduce the image-processing bottleneck.
Although SDRAM has a higher data access rate than DRAM due to a burst mode, the advantage of the burst mode in a scanner is not always realized. This is due to that some of the data in a scanner are stored as random numbers, for example, in a gamma table.
Accordingly, one object of the present invention is to provide a method of reading data from a synchronous dynamic random access memory (SDRAM) inside a scanner. The reading method utilizes the burst mode and the multi-bank arrangement of a SDRAM for a faster data read-out rate.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a method of reading data from a synchronous dynamic random access memory (SDRAM) inside a scanner. The SDRAM has a plurality of memory banks. A batch of random access data is stored inside any one of the memory banks and a batch of burst data capable of operating in the burst mode is stored in any other memory bank. The command for reading the random number data and the burst mode command for transmitting burst mode data are issued concurrently.
In addition, a pre-charge command for pre-charging the memory bank holding the random number data is executed before obtaining the random number data.
In brief, irregular data such as the data in a gamma table are independently stored in a memory bank inside a SDRAM. Hence, interleave bank access and burst mode transmission can be executed together when random access is required. As a result, there is no need to wait commands for pre-charging and triggering the memory bank before initiating data access, all of which conventionally occur in the same memory bank.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.